scholarly journals Uneven Distribution of Mating Types among Genotypes of Candida glabrata Isolates from Clinical Samples

2009 ◽  
Vol 8 (3) ◽  
pp. 287-295 ◽  
Author(s):  
Sylvain Brisse ◽  
Christine Pannier ◽  
Adela Angoulvant ◽  
Thierry de Meeus ◽  
Laure Diancourt ◽  
...  
Keyword(s):  
Mating Type ◽  
Candida Glabrata ◽  
Tandem Repeats ◽  
Minimum Spanning Tree ◽  
Variable Number ◽  
Clinical Samples ◽  
Population Genetic Analysis ◽  
Pathogenic Yeast ◽  
Diploid Genotype ◽  
Mating Type Switching

ABSTRACT In order to shed light on its basic biology, we initiated a population genetic analysis of Candida glabrata, an emerging pathogenic yeast with no sexual stage yet recognized. A worldwide collection of clinical strains was subjected to analysis using variable number of tandem repeats (VNTR) at nine loci. The clustering of strains obtained with this method was congruent with that obtained using sequence polymorphism of the NMT1 gene, a locus previously proposed for lineage assignment. Linkage disequilibrium supported the hypothesis of a mainly clonal reproduction. No heterozygous diploid genotype was found. Minimum-spanning tree analysis of VNTR data revealed clonal expansions and associated genotypic diversification. Mating type analysis revealed that 80% of the strains examined are MAT a and 20% MATα and that the two alleles are not evenly distributed. The MAT a genotype dominated within large clonal groups that contained only one or a few MATα types. In contrast, two groups were dominated by MATα strains. Our data are consistent with rare independent mating type switching events occurring preferentially from type a to α, although the alternative possibility of selection favoring type a isolates cannot be excluded.

scholarly journals Identification of a member of a DNA-dependent ATPase family that causes interference with silencing.

1997 ◽  
Vol 17 (9) ◽  
pp. 5461-5472 ◽  
Author(s):  
Z Zhang ◽  
A R Buchman
Keyword(s):  
Mating Type ◽  
Tandem Repeats ◽  
Specific Interaction ◽  
Cis Acting ◽  
Cellular Processes ◽  
Protein Dna Interactions ◽  
Mating Type Switching ◽  
Silencer Elements ◽  
Dna Template ◽  
Knockout Mutation

DNA in eukaryotic cells is packed in tandem repeats of nucleosomes or higher-order chromatin structures, which present obstacles to many cellular processes that require protein-DNA interactions, such as transcription, DNA repair, and recombination. To find proteins that are involved in increasing the accessibility of specific DNA regions in yeast, we used a genetic approach that exploited transcriptional silencing normally occurring at HML and HMR loci. The silencing is mediated by cis-acting silencer elements and is thought to require the formation of a special chromatin structure that prevents accessibility to the silenced DNA. A previously uncharacterized gene, termed DIS1, was isolated from a screen for genes that interfere with silencing when overexpressed. DIS1 encodes a protein with conserved motifs that are present in a family of DNA-dependent ATPases, the SWI2/SNF2-like proteins. Overproduction of N-terminal half of DIS1 protein interfered specifically with ectopic silencing used in the screen as well as HMR E silencing. Two-hybrid studies revealed a specific interaction between the N terminus of DIS1 and the C-terminal half of SIR4, a protein essential for silencing. Cells with a dis1 knockout mutation had significantly lower mating-type switching rate. These results suggest that DIS1 may contribute to making the silenced DNA template at HM loci more accessible during the mating-type switching process.

scholarly journals A Snapshot of the Genetic Diversity of Salmonella Enteritidis Population Involved in Human Infections in Romania Taken in the European Epidemiological Context

Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1490
Author(s):  
Codruta-Romanita Usein ◽  
Mihaela Oprea ◽  
Adriana Simona Ciontea ◽  
Sorin Dinu ◽  
Daniela Cristea ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Salmonella Enteritidis ◽  
Tandem Repeats ◽  
High Throughput Sequencing ◽  
Minimum Spanning Tree ◽  
Public Health Practice ◽  
National Level ◽  
Variable Number ◽  
Integrative Approach ◽  
Sequencing Data

In the absence of consistent national molecular typing data to enhance the surveillance of Salmonella Enteritidis, it was considered useful to collect baseline information on the genetic diversity and antibiotic susceptibility of strains isolated in Romania between January 2016 and April 2020 and compare them to strains described in major international outbreaks of the same period. A collection of 245 clinical isolates were genotyped by a standardised multiple-locus variable-number of tandem repeats analysis (MLVA) 5-loci protocol and screened for antimicrobial resistance against 15 compounds. Twenty strains were further subjected to whole genome sequencing (WGS) and compared to epidemiologically relevant high-throughput sequencing data available in European databases. Twenty-seven MLVA genotypes were identified, of which three, commonly reported in Europe between 2016–2020, covered 72% of the collection. Antibiotic resistance was detected in 30% of the strains, with resistance to nalidixic acid and ciprofloxacin as the most common phenotype, and also associated with two prevalent MLVA clones. WGS-derived multilocus sequence typing (MLST) revealed a single sequence type (ST11) further resolved into 10 core-genome MLST complex types. The minimum spanning tree constructed from the cgMLST data clustered Romanian and international strains, which shared more than 95% of the core genes, revealing links with a contemporaneous multi-country outbreak. This study could be regarded as a forerunner to the advent of using this integrative approach in the public health practice at a national level and thus contribute to the concerted actions at a European level to stop outbreaks.

scholarly journals First Molecular Characterisation of Clinical Strains of Mycobacterium ulcerans in Togo (West Africa)

2019 ◽  
pp. 1-14
Author(s):  
Menssah Teko ◽  
Mounerou Salou ◽  
Solange E. Kakou Ngazoa ◽  
Issaka Maman ◽  
Kodjovi Agbodeka ◽  
...  
Keyword(s):  
West Africa ◽  
Tandem Repeats ◽  
Buruli Ulcer ◽  
Variable Number ◽  
Mycobacterium Ulcerans ◽  
Clinical Samples ◽  
Molecular Technique ◽  
Endemic Region ◽  
Typing Method ◽  
Genetic Strains

Background: Buruli ulcer is the third most common mycobacterial disease worldwide. Cases most occur in 30 countries but severe cases occur in West Africa countries such as Benin, Cote d’Ivoire and Togo mainly in rural regions. Early diagnosis may prevent severe disability. The molecular technique seems the best solution and new Mycobacterial Interspersed Repetitive Units (MIRU) and variable number tandem repeats (VNTR) typing method are themost reproducible in this regard. They propose geographical, inter and intraspecies differentiation and can be used as a diagnosis tool. Objective: The objective of this study was to investigate the molecular diversity by using MIRUVNTR typing in clinical samples of BU patients in Togo. Study Design: 64 DNA extracts from clinical samples were collected from BU patients in the two principal endemics districts in Togo (Yoto and Zio) with three less endemic districts (Bas Mono, Lacs and Vo). First, IS2404 and KR real-time PCR plus IS2606 conventional PCR were performed. In a second step, the strains were analysed by PCR typing for five specific and sensitive markers MIRU1, VNTR6, ST1, VNTR19 and VNTR9. Results and Conclusion: 71.11% were positive for IS2404, 3.13% were positives for PCR-KR and 31.11% for IS 2606. By MIRU-VNTR typing, 48.86% positive result was found for MIRU1 and 25.00%, 20.31%, 18.75% and 14.06% for VNTR6, ST1, VNTR19 and VNTR9 respectively. One of the samples was negative for all genotyping markers. Two different genetic profiles were identified by MIRU1, ST1 and VNTR loci by gel-analysed of the amplified products. The VNTR profile B (3,1,1,2) corresponding of 3 copies MIRU1, 1 copy VNTR6, 1 copy ST-1 and two copies of VNTR19 was detected in 15.63% of samples and the VNTR profile A (1,1,1,2) corresponding of 1 copy MIRU1, 1 copy VNTR6, 1 copy ST-1 and 2 copies of VNTR19 was detected in 3.13% of samples and confirms the West African genotype (3,1,1) in Togo. Different genetic strains of Mycobacterium ulcerans (M. ulcerans) were co-circulated in the same endemic region in the country. This study has described first the circulating of different genetic strains of M. ulcerans in Togo.

scholarly journals A single Ho-induced double-strand break at the MAT locus is lethal in Candida glabrata

2020 ◽  
Author(s):  
Laetitia Maroc ◽  
Youfang Zhou-Li ◽  
Stéphanie Boisnard ◽  
Cécile Fairhead
Keyword(s):  
Cell Death ◽  
Sexual Reproduction ◽  
Mating Type ◽  
Candida Glabrata ◽  
Strand Break ◽  
Double Strand Break ◽  
Switching System ◽  
Massive Cell Death ◽  
Mating Type Switching ◽  
Massive Cell

AbstractMating-type switching is a complex mechanism that promotes sexual reproduction in Ascomycotina. In the model species Saccharomyces cerevisiae, mating-type switching is initiated by the Ho endonuclease that performs a site-specific double-strand break (DSB) at MAT, repaired by homologous recombination (HR) using one of the two silent mating type cassettes, HMLalpha and HMRa. The reasons why all the elements of the mating-type switching system have been conserved in some Ascomycotina, that do not show a sexual cycle nor mating-type switching, remain unknown. To gain insight on this phenomenon, we used the opportunistic pathogenic yeast Candida glabrata, phylogenetically close to S. cerevisiae, and for which no spontaneous and efficient mating-type switching has been observed. We have previously shown that expression of S. cerevisiae’s HO gene triggers mating-type switching in C. glabrata, but this leads to massive cell death. In addition, we unexpectedly found, that not only MAT but also HML was cut in this species, suggesting the formation of multiple chromosomal DSBs upon HO induction.We now report that HMR is also cut by S. cerevisiae’s Ho in wild-type strains of C. glabrata. To understand the link between mating-type switching and cell death in C. glabrata, we constructed strains mutated precisely at the Ho recognition sites. By mimicking S. cerevisiae’s situation, in which HML and HMR are protected from the cut, we unexpectedly find that one DSB at MAT is sufficient to induce cell death. We demonstrate that mating-type switching in C. glabrata can be triggered using CRISPR-Cas9, without high lethality. We also show that switching is Rad51-dependent, as in S. cerevisiae but that donor preference is not conserved in C. glabrata. Altogether, these results suggest that a DSB at MAT can be repaired by HR in C. glabrata, but that it is prevented by S. cerevisiae’s Ho.Author summaryMating-type switching is one of the strategies developed by fungi to promote crossing, sexual reproduction and propagation. This mechanism enables one haploid cell to give rise to a cell of the opposite mating-type so that they can mate together. It has been extensively studied in the model yeast S. cerevisiae in which it relies on a programmed double-strand break performed by the Ho endonuclease at the MAT locus which encodes the key regulators of sexual identity. Little is known about why the mating-type switching components have been conserved in species like C.glabrata, in which neither sexual reproduction nor mating-type switching is observed. We have previously shown that mating-type switching can be triggered, in C. glabrata, by expression of the HO gene from S. cerevisiae but this leads to massive cell death. We report here evidence toward a degeneration of the mating-type switching system in C. glabrata. We demonstrate that the DSB at MAT is only lethal when the Ho endonuclease performs the break, a situation unique to C. glabrata. Finally, we show that mating-type switching in C. glabrata can be triggered by CRISPR-Cas9 and without any high lethality.

scholarly journals Efficient Mating-Type Switching in Candida glabrata Induces Cell Death

PLoS ONE ◽  
2015 ◽  
Vol 10 (10) ◽  
pp. e0140990 ◽  
Author(s):  
Stéphanie Boisnard ◽  
Youfang Zhou Li ◽  
Sylvie Arnaise ◽  
Gregory Sequeira ◽  
Xavier Raffoux ◽  
...  
Keyword(s):  
Cell Death ◽  
Mating Type ◽  
Candida Glabrata ◽  
Mating Type Switching

scholarly journals Multilocus VNTR analysis of Mycobacterium ulcerans strains isolated in Côte d’Ivoire

2010 ◽  
Vol 5 (01) ◽  
pp. 059-063 ◽  
Author(s):  
Grossmann Marie-David Coulibaly-N´Golo ◽  
Euloge Ekaza ◽  
Bakary Coulibaly ◽  
N’guetta Aka ◽  
Raymond Kouassi N’Guessan ◽  
...  
Keyword(s):  
Cote D'ivoire ◽  
Tandem Repeats ◽  
Côte D’Ivoire ◽  
Buruli Ulcer ◽  
Variable Number ◽  
Mycobacterium Ulcerans ◽  
Clinical Samples ◽  
Bacterial Strains ◽  
Cote D’Ivoire ◽  
Côte D'ivoire

Introduction: Buruli ulcer, caused by Mycobacterium ulcerans, is endemic in more than 30 countries worldwide, with Côte d'Ivoire being among the most affected countries. Methodology: We used seven variable number of tandem repeats (VNTR) markers and analyzed 114 samples from 11 Ivorian localities consisting of 33 bacterial strains and 81 clinical samples. Complete data sets at loci 1, 6, 9 and 33 were obtained for 18 of these strains (n = 15) and samples (n = 3) collected in each of the localities. Results: All the strains had allelic profile [3113], corresponding to the previously described Atlantic Africa genotype. Conclusion: Sequencing of PCR products at all loci showed no variation in sequence or repeat number, underlining the genetic monomorphism of M. ulcerans in Côte d'Ivoire.

scholarly journals Phenotypic Switching and Mating Type Switching ofCandida glabrata at Sites ofColonization

2003 ◽  
Vol 71 (12) ◽  
pp. 7109-7118 ◽  
Author(s):  
Paula J. Brockert ◽  
Salil A. Lachke ◽  
Thyagarajan Srikantha ◽  
Claude Pujol ◽  
Rudolph Galask ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mating Type ◽  
High Frequency ◽  
Candida Glabrata ◽  
Phenotypic Switching ◽  
Vaginal Infection ◽  
Vaginal Colonization ◽  
Type Classes ◽  
Mating Type Switching ◽  
Oral Colonization

ABSTRACT Candida glabrata switches spontaneously at high frequency among the following four graded phenotypes discriminated on agar containing 1 mM CuSO4: white, light brown, dark brown (DB), and very dark brown. C. glabrata also contains three mating type loci with a configuration similar to that of the Saccharomyces cerevisiae mating type cassette system, suggesting it may also undergo cassette switching at the expression locus MTL1. To analyze both reversible, high-frequency phenotypic switching and mating type switching at sites of colonization, primary samples from the oral cavities and vaginal canals of three patients suffering from C. glabrata vaginitis were clonally plated on agar containing CuSO4. It was demonstrated that (i) in each vaginitis patient, there was only one colonizing strain; (ii) an individual could have vaginal colonization without oral colonization; (iii) phenotypic switching occurred at sites of colonization; (iv) the DB phenotype predominated at the site of infection in all three patients; (v) genetically unrelated strains switched in similar, but not identical, fashions and caused vaginal infection; (vi) different switch phenotypes of the same strain could simultaneously dominate different body locations in the same host; (vii) pathogenesis could be caused by cells in different mating type classes; and (viii) mating type switching demonstrated at both the genetic and transcription levels occurred in one host.

Sign in / Sign up

Export Citation Format

Share Document